The present invention relates to an improved method and apparatus for use in cutting submarine casing and retrieving such casing and the other equipment on the ocean floor. One particular reason for this operation is the removal of equipment which might create a hazard if it were to remain in place on the ocean floor.
U.S. Pat. No. 3,983,936 discloses one method which cuts and recovers such submarine wellhead equipment. It involves the steps of lowering a string including a casing cutter, a spear and a swivel and landing the swivel on the upper end of the casing. The cutting is commenced and when complete the spear is expanded to firmly engage within the casing to allow it to be raised as the string is recovered.
Another patent disclosing, a modified form of such method, is U.S. Pat. No. 4,191,255. It differs from the U.S. Pat. No. 3,983,936 in that it maintains the spear above the upper end of the casing during cutting and then when cutting is complete, is lowered into the cut casing and set so that the submarine wellhead equipment may be raised with the string and thereby recovered from the ocean floor.